The proposed research is designed to study electrical coupling between cones and between horizontal cells in the turtle retina. Two electrodes will be used to record simultaneously from pairs of cells. Electrical interactions will be studied directly by passing current into one cell while recording the resulting voltage change in the other cell. Attention will be paid to the spectral and spatial properties of coupled cells. The goal is to study extensively the organization and electrical properties of the different electrically coupled cell networks. The two electrode method will also be used to investigate the electrical events that give rise to the light response in cones.